Vector network analyzers (VNAs) are devices that are used to determine the radio frequency (RF) characteristics of various devices under test (DUTs). For a number of VNA operations, the pertinent performance measurements depend upon both the magnitude and phase of the signals applied to and received at each port. However, the delay and attenuation to a DUT may vary on a per port basis. For example, fixture-based test set-ups and “on wafer” set-ups may cause such differences to occur. Specifically, transmission line characteristics can significantly effect the phase and amplitude measurements of a DUT.
Most commercially available VNAs include some functionality to address transmission line effects. An example of such functionality is referred to as “port extensions” that adjust the phase and/or amplitude of measurement data according to an electrical length parameter. Known port extension functionality assumes that a linear relationship exists between the electrical length of a transmission line to the DUT and the delay. However, many transmission lines are dispersive and, hence, their phase characteristics are not linear with respect to frequency. The use of a linear model to compensate for transmission line characteristics can result in significant inaccuracies for higher frequency applications. Another example of such functionality is referred to as “adapter removal” that attempts to remove the magnitude and phase response of an adapter.